Blackboard-eraser.



G. P. LULL. BLAGKBOABD ERASER.

APPLICATION FILED MAB.. 3, 1911.

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o o o o o o o o @V Q o o c o o o *rif OOCOOOOOOOOOOGOO -lli 1L @n m Geofgmzuu, by M sneed-n r. LULL, or BRADFORD, PENNsofnvnuza,"I

,Beherrschen-uname.

- specification of Letters Patent. Patented June 13, H1. i

imputation med March s. 1911. serial No.' 612,157'.`

lb all wlw/cn it concern:

Be it known that l, Gnouon LULL, citizen of the United States, residing at ABradford, Pennsylvania, have invented certain 5: new and useful improvements in Blacklll boardslllrasers, of which the following is a specification.

My present invention relates to improvements in blackboard cleaners or erasers and y.hastor itszobjcct to produce a device which niay be easilyandetl'ectivcly used to clean oil blackboards without causing dust to be disseminated throughout the room to the discomfort and` injury ot the occupants thereof.

An eraser constructed in accordance with my invention is illustrated in the acconpanying drawing inwhich- 'Figure l is a side elevation, partly in section. 2 is an end view, also partly in section, and Figt vis a front view of a portion of a blackboard illustrating the use of the cleaner. l is a bottom plan view of the cleaner .with the felts removed;

My black board cleaner is adapted to be used in a building equipped with piping for vacuum cleaning purposes. l. have shown in the drawing a portieri of such piping, as indicated in dotted lines in Fig. 3, and connected with a flexible tube 3 to my. eraser 4, shown diagrammatically in connection with' the blackboard. The connection of the flexible pipe or hose with. the fixed piping is shown at 2 and at that place may be located any suitable shut oil valve.

The eraser is specially designed to be used by children, and especially adapted to be grasped by their hands operating at the same time the valve by which the exhaust is put in action. The eraser comprises a hollow main vacuum chamber l made in narrow .elongated form, adapted to be grasped by the hand of' a child, the form of the sides being' clearly shown 'in Fig. 2. Below this main chamber is a felt carrier. the Walls oi which, when the eraser is applied to the blackboard form a secondary ..r chamber which in connection with the main cham-- ber by a series of holes throughout its entire lengt-h. rlhe felt or equivalenttiln'ous `material shown at G vis inelosed and held b v walls, as illustrated in l and 2, and a central longitudinal felt strip 6 similarly held-occupies the center, shown in Fig. Q; The main part the rubbing surface ot telt marlled', is on the sides and ends, shown in Fig. Il, the interior strip Ga being shown also in this figure, which is a l'iottomview. The inclosing walls which hold the felt are fixed to :t plate 'formed with perforations which register with like perforations in the bottom of the main chamberxto which said reruns plate is removably hold by screws 20, wheres' by the rubbing surfaces may be renewed when worn. v

[is shown the .telt holder comprises the spaced downwardly flaring. open Vbottomed hollow members 8, parallel with each other and with the sides of the'cleaner, and thel outer member 8 having depending couver.v

of the sides and ends ofthe body of the cleaner, and spaced trom the members 8. The outer member, as shown, is held to the body by the flaring walls of the inner members.

It. will be observed that the narrow rubbing strips (3 form tbe'walls of the lower exhaust chamber so that the force of the exhaust is across this narrow strip and the dust displaced by the rubbing surfaces, is acted upon directly andstrongly by the exhaust, and completely drawn across this narrow margin into the lower chamber, and it is also drawn equally all around the edge oit' the workiiig face of the eraser. In erasers of this class it is necessary that the exhaust should be shut oita automatically when the eraser is not in use. Further, it is desirable that the exhaust should be established easily when the eraser is in use. ln order that it may be easily and elfcct'ually established by the user, even though a child, I have provided a plunger' 13 passing through a suitable packed opening in the top wall of the body or case and this is provided with a head 13, adapted to be pressed upon by the palm of the hand, so that in grasping the cleaner and pressing it against the blackboard the plunger is pushed in by the palm of the hand coming in contact with the plunger head and by the torce exerted in pressing the eraser against the board.' This plunger operates uponlaniarm l1. pivoted at ll to a projection l2 inside of the case. lt

is connected by a link l0 to the hinged valve 9 located at thc orifice andl covering the mouth of the exhausty pipe. A light spring l/lholds the plunger up when not in use.

lWhile the apparatus is especially adapted to blackboards and for use for children, it may of course be used for other purposes.

70 gent walls extending along the lower ,edgesV roo With a construction Isuch as described the mere pressure-of the cleaner a ainst the 'blackboard opensthe valve an as itis ymoved over the blackboard and the felts remove the dust the latter'is drawn into the body of the cleaner and thence to the piping and into the collection 'receptacle (not shown).

I have lfound that a cleaner -such as hereinbefore` described is also' speciali)7 adaptedA for and eicient inthe cleanin 'cleaner may be suspended-when not in use.

l v grasped eo i elongatedl vacuum chamber' adapted to be I claim isz;

' Having thus described "my invention what 1. A pneumatic cleaner comprising a main Y :elongated vacuum 'chamber adapted to be the' hand of the user, a: corre-Y spondin'ge ongated chamber below said vacuum chamber, and in communication:there-V 2. A pneumatic cleaner comprising a main exible exhaust grasped by the of the user,- a corresponding elongate'd'chamber below said vacuum chamber and in vconnection therewiththroughout its length, said llower chamber bein surrounded by a wall surfaced with rubbln material, a valve for shuttin of the ex 'aust,'said valve being operated by means of a sprin knob located onv the top tube connected withsaid main chamber, substantially as described.

3. eraser or cleaner consisting of a hollow elongated body, having means for connection with an exhaust' hose, and a felt of the main cham er, and a flexiblel exhaust I holder comprising the spaced downwardly I 'flaring open .bottomed hollow members 8A,

parallel with each lother and with the sides of thecleaner, and the' outer member 8. ha`v` ing depending convergent walls extending along the lower edges of. thesi'des and ends.

of' the body rof the cleaner, and s aced from theA members 8,v substantiallyl as escribed.

1n testimony whereof, I aHiX my signature in presence -of two witnesses. v'

' Witnesses: EDMUND BURNS,

RUrUs B. STONE. 

